Interfaces. User Interface

1. Interfaces

2. User Interface

The user interacts with a computer system
through its user interface. The user gives input
and receives responses from the computer.
A user interface also called a human-computer
interface (HCI) consists of both hardware and
software.

3. Graphical User Interface(GUI)

Graphical User Interface uses:
Windows
Icons
Menus
Pointing device
GUI is called a ‘WIMP’ interface.
The windows explorer program uses multi-level
menus. The desktop and taskbar has icons to
represent various programs.

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The principle of a GUI is to make using the
system as simple as possible by hiding all the
complicated steps.
For example, when the user clicks an icon to
bring a piece of software onto the screen.
It involve only one action but in the
background computer is executing
complicated process involving a lot of
instruction.

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The user can switch from one task to another.

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Advantages
Disadvantages
This type of user interface is easy to use,
especially for a beginner
GUIs take up a much larger amount of
hard disk space than other interfaces
It is easy to explore and find your way
around the system using a WIMP/ GUI
interface
They need significantly more memory
(RAM) to run than other interface types
You do not have to learn complicated
commands
They use more processing power than
other types of interface
There are usually good help facilities
provided with WIMP interfaces
They can be slow for experienced
programmers to use. These people often
find CLI interfaces faster to use

8. Command Line Interface

The user needs :
To know the commands
To understand the commands
To understand how material is stored in the
computer system.
The computer system is very much open than in the
other types of inteface. A command line interface
allows anyone with a knowledge of the commands
access to the entire operating system.

9. Command Line Interface

The use is presented with command line prompt.
The user must learn and then use the commands.
The traditional command-line interface on the PC
was the early MS-DOS operating system from
Microsoft.
Eg., dir – which displays the list of all the files &
folders in the current folder.
Command Line interfaces have advantage that once
the commands have been learnt an expert user
can quickly use the computer system.

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Advantages
Disadvantages
If the user knows the correct commands
then this type of interface can be much
faster than other types of interface
For someone who has never used a CLI, it
can be very confusing
This type of interface needs much less
memory (RAM) in order to use it than
other user interfaces
Commands have to be typed precisely. If
there is a spelling error the command will
fail
This type of interface does not use as
much CPU processing time as others
If you mis-type an instruction, it is often
necessary to start from scratch again
A low resolution, cheaper monitor can be
used with this type of interface
There are a large number of commands
which need to be learned - in the case of
Unix it can be hundreds

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Disadvantage
• Users have to learn and remember a
command language.
• Users make errors in command.
• Not suitable for casual or inexperienced users

12. Natural Language Interface

Natural language processing is the ability to
communicate with computer system using
natural language.
Eg., Carrying out a keyword search.
Consider a search for the text “Which city in
England has the largest population outside
London”.
A keyword search would only focus on
“Population” and “London”

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Ask.com use natural language processing for analysis of search engine text.

14. NLP

An example of a natural language interface
which makes use of written text is a 'chat bot'.
This software mimics a conversation - you ask
it questions and it will come back with a
suitable comment for you.
http://nlp-addiction.com/eliza/

15. NLP

Advantages
Disadvantages
The user does not need to be trained in
how to use the interface
Reliability remains an issue - the interface
can only respond to commands that have
been programmed
Suitable for physically handicapped
people
Not widely available as other forms of
interface are often superior

16. Form based Interface

Many applications are web-based and require the
completion of a form for data capture. The shows
the entry of the data for ordering online.
The form contain the usual ‘widget’ controls for
data entry including:
• Text boxes
• Radio button
• Check boxes
• Drop Down lists

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Advantages
Disadvantages
Easy to program
Only limited options presented
Easy for user to see the options available
Visually impaired people might have
trouble seeing the text or options
Data validation can be used on data entry
forms
Not good for highly complex applications,
for example, a tax form might have 20
pages of options that need to be
completed
Fast to enter data or to make choices
Little or no training required
They don't need huge amounts of
processing power or memory

19. Menu based Interface

The majority of windows-based applications
software is menu-driven. That is the user is
presented in various possible forms with the
number of menu choices. Making a selection may
result in a second or more set of choices being
presented.
• A well designed menu interface is simple to use,
you just follow the instructions and make your
choices.
• User dont need to remember the command.
• Typing is minimal

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Advantages
Disadvantages
Extremely easy to use
A poorly designed menu interface may be
slow to use
There are no commands to learn or
remember
It can be irritating if there are too many
menu screens to work through - users get
annoyed or bored if it takes too long
Step-by-step options are given so that the
user doesn't have to remember anything
You often can't go to the exact place you
want right at the start. You have to work
your way through the menu screens even
if you know where you want to get to.
Even if you don't know what to do, you
can usually guess your way round the
options
The menu can take up a large part of the
screen so you have to keep flicking back
and forwards between applications
Menu interfaces don't have to be visual,
they can be spoken - good for telephones
or for visually impaired people
If the menu is poorly designed it might be
hard to read e.g. writing is too small for
people with poor sight, colours might
clash and be difficult to read, font style
might be hard to read.

21. Questions

1. Which user interface provides a series of step-by-step
options from which the user can select their choice?
2. Which user interface requires a detailed knowledge of
the commands?
3. Which interface provides the benefits of WYSIWYG?
4. Which of the following user interfaces uses the least
amount of memory?

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5. Which user interface makes use of switches?
6. Which user interface is most likely to be used at cash
point?
7. Which user interface uses the most processing power?
8. Which user interface enables users to open
applications by clicking on the shortcut icons on the
desktop?

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9. Which interface would probably be used to enter
data into a database?
10. Which user interface requires detailed
knowledge of the commands?
11. Which interface is otherwise known as a WIMP
interface?

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http://www.bbc.co.uk/schools/gcsebitesize/ict/s
oftware/5userinterfaces_act.shtml